You may notice that fine lines look more obvious on some days than others, even when you have not suddenly aged overnight. Science suggests the weather can play a role. Changes in relative humidity can alter the water content, elasticity and surface texture of the skin, making wrinkles temporarily appear deeper or less noticeable.
The reason begins with the skin's outermost layer: the stratum corneum. Rather than being an inert covering, this layer constantly regulates water movement between the body and the environment. Its corneocytes contain water-attracting substances called the natural moisturizing factor (NMF), while surrounding lipids help limit water loss.
